Safety latch

ABSTRACT

A safety latching device pivotally connected to the periphery of a cover closing a pressurized container for providing an increment of free displacement of the cover to thereby facilitate depressurization of the container. The latching device includes a latch pivotally suspended from the cover, such latch further including a weight bias distal the pivot when normally disposed to suspend an inwardly extending projection into engaging alignment below a cooperating catch formed on the container. Further included on the container is a permanent magnet aligned in opposition to the latch for maintaining the latch in engaging alignment. The pivotal motion of the latch is limited to form a handle in an extended position and to preclude any impact of the latch against the magnet.

United States Patent 91 Elrod et a1.

[ Oct. 29, 1974 [54] SAFETY LATCH 22 Filed: Aug. 29, 1973' 21App1.No.:392,533

[52] 11.8. CI. 292/251.5, 292/136 [51] Int. Cl. E05c 19/16 [58] Field ofSearch 292/130, 131, 136, 251.5, 292/238, DIG. 14, DIG. 15, DIG. 30;

' 220/553, DIG. 17

[5 6] References Cited UNITED STATES PATENTS 478,245 7/1892 Smith ..l292/2515 X 814,702 3/1906 Honecker et al.. 292/136 2,318,151 5/1943 Gary292/136 X 6/1952 Schweiso ..220/55.3 12/1957 Ramsey ..292/D1G.14

[5 7 ABSTRACT A safety latching device pivotally connected to theperiphery of a cover closing a pressurized container for providing anincrement of free displacement of the cover to thereby facilitatedepressurization of the container. The latching device includes a latchpivotally suspended from the cover, such latch further including aweight bias distal the pivot when normally disposed to suspend aninwardly extending projection into engaging alignment below acooperating catch formed on the container. Further included on thecontainer is a permanent magnet aligned in opposition to the latch formaintaining the latch in engaging alignment. The pivotal motion of thelatch is limited to form a handle in an extended position and topreclude any impact of the latch against the magnet.

7 Claims, 4 Drawing Figures I '1 SAFETY LATCH BACKGROUND OF THEINVENTION I 1. Field of the Invention The present invention relates tosafety latches, and

more particularly to safety latches mounted on horizontally disposedaccess covers containing pressurized V gases.

cover is usually such that even small pressure differentials thereacrosssum up tolarge force levels and such large force levels, particularly onrelease, provide a source of hazard to loading personnel. Heretofore,prior hatch covers of this kind usually included pressure releasedevices, either of the vent type or of the latch type, where thelatchtype permitted a partial opening of the cover-to-port interface,releasing the pressure stored therein and thereby facilitatingconvenient and safe opening. Particularly the latter, i.e., the latchtype releases, most always included biasing springs for maintaining alatching alignment of the latch providing an increment of freedisplacement between the latch and the cooperating catch. The operationof the springs biasing such prior art latches therefore had to bereliable since the whole safety feature functioning of the latch wasdependent on the structural and elastic integrity thereof. Particularlywhen considered with the typical handling and environment abuse thatsuch a latch is exposed to, the inclusionof a bias spring presented areliability consideration as well as a continuing safety hazard.

SUMMARY OF THE INVENTION Accordingly, it is the general purpose andobject of the present invention to provide a safety latch disposed toaccommodate an increment of free displacement between the latchingsurface thereof and a cooperating catch, such latch being maintained ina latching position by the weight bias thereof. Other objects of theinvention are to provide a safety latch normally imbalanced to hang in avertical position in engaging alignment with an associated catch, themotion of the latch being limited around a pivot to form a handle whenextended from its engaging position, and to provide magnetic structureopposite the latch for attracting the latch to an engaging positionduring transit.

Briefly, these and other objects are accomplished within the presentinvention by providing a safety latch pivoted at one end thereof fromintermediate two hinge ears formed to extend from the periphery of apressurized container cover, the weight distribution of the latch aboutthe pivot being such as to bias the normal suspended position thereoffrom the hinge pin in a cooperating alignment with a catch formed on theperipheral side of the container. To assure further continued alignmentof the latch during transit vibrations and during transients associatedwith any stationing and loading manipulations, a permanent magnet isattached to the exterior surface of the container in opposing proximitywith the free end or engaging portion'of the latch, such magnetmaintaining the latch in position until manually withdrawn from suchposition. The latch furthermore includes on the pivotal or upper endthereof a radial extension terminating in a bearing surface whereby thepivotal motion of the latch about the hinge pinis limitedto asubstantially horizontal position thus providing a handle formanipulating the cover. The inward travel of the latch is furtherlimited by an abutting structure protruding therefrom such that directimpact of the latch against the magnet is precluded.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of apressurized container constructed according to the present invention;

FIG. 2 is a front section view of an inventive latch constructedaccording to the present invention;

FIG. 3 is a side view, in partial cross-section, taken along the line3-3 of FIG. 2; and

FIG. 4 is a cross-sectional view taken along line 44 of FIG. 2.

DESCRIPTION OF THE SPECIFIC EMBODIMENT end from the periphery of ahorizontal access cover 27 to align the free end thereof for engagementof a projection 28 extending therefrom below a cooperating catch 31,formed on a container 30, allowing a predetermined increment ofseparation of the cover 27 from the container 30. The latching lever 20is pivotally secured to a hinge pin 21 received within two opposed axialbores 22 and 23 extending across two vertically aligned hinge cars 25and 26 formed on the periphery of cover 27, the hinge pin 21 engagingtherebetween a pivot bore 29 formed in the one end of the latching lever20. The paired ears 25 and 26 project from the periphery of thehorizontal access cover 27 closing the pressurized container 30 at apoint substantially diametrically opposite to a cover hinge 37 aboutwhich the cover pivots. As described in more detail hereinbelow, thepivotal freedom of motion of latching lever 20 about the hinge pin 21 islimited to angular rotation of substantially one quadrant, between avertically hanging position and a substantially horizontal or extendedposition. Thus the latching lever 20 provides a handle structure whenextended to a horizontal position for facilitating articulation of thecover 27' about hinge 37 after such cover is released from a sealingengagement with container 30 upon release of a plurality of overcenterlatches 35. When released, the latch lever 20- More specifically, asshown in FIGS. 2 and 3, the I upper end of the latching lever 20 isextended along a radius substantially transverse to the longitudinalaxis thereof from the hinge pin 21 to provide a bearing surface P whichabuts a cooperating surface F on the exterior of the cover 27 when suchlatch is extended to a horizontal position. in this manner the angularmotion of the latching lever is restricted in one direction to providehandling convenience for raising the cover 27. The amount of the inwardrotation of the latching lever 20 about hinge pin 21 is also limited bya projection D extending, again transversely inward from the lever 20,below the central axis of the hinge pin to abut an opposed cooperatingperipheral edge of cover 27. The relative dimension of the projection Dis such that direct impact of the free end of lever 20 against theadjacent side of the container is precluded. Thus the lever 20 is freeto articulate between a horizontal position and a vertical or hangingposition being biased in the hanging position by the weight distributionthereof around the hinge pin 21 to provide a steady state momentthereabout, urging the free end of the lever towards the adjacent sideof container 30 for latching alignment. More specifically, the exterioredge of the latching lever 20, or the edge distal of pin 21, is expandedto form laterally opposed ribs 38 and 39 providing a large weightconcentration distal of a vertical plane intersecting the hinge pin 21,and thereby providing a weight bias distally lateral of the hinge pinaxis for biasing the latching lever into an engaging alignment forlatching with the catch 31 mounted on the exterior of container 30. Theinterior edge of the latching lever 20 extends transversely at the freeend thereof towards the opposing container surface to form theprojection 28, such projection extending upwardly along an interior edgeadjacent to pin 21 to terminate in an engaging surface a predeterminedincrement below the catch 31 when the cover 27 is in a closed position.This distance between the cooperating surfaces of projection 28 andcatch 31 provides for a partial opening of cover 27 before engagement,whereby any interior pressurized gases are allowed to escape, releasingthe force built up on the cover. To further assure continued alignmentof latching lever 20 in a cooperating state between the end ofprojection 28 and catch 31 a permanent magnet 32 is affixed, again tothe exterior of container 30, in opposing relationship with the free endof projection 28. lt is to be noted that the dimensioning of projectionD is such that no direct contact is made between the free end ofprojection 28 and the magnet 32, thus preventing direct impacts on thepermanent magnet.

In this manner, a pressure release latch is provided which allows for apartial opening of the cover to release any gases retained thereby, suchopening being possible only after the other closure devices on the coverare opened. Thus, an operator is assured that the hatch, on opening,will not be thrown open beyond the catching dimensions provided in thelatch assembly 10.

In operation, the cover 27 is normally secured to the peripheral edge ofthe container 30 by the plurality of conventional over-center latchingdevices. When the last latching device 35 is released, the pressurecollected below the cover forces the cover away from the container atwhich time the projection 28 extending from the latching lever 20 limitsthe amount or the displacement of the cover. Once the pressurized gasesare released, the cover then falls back onto the peripheral edges of thecontainer 30 and can be freely opened by grasping the latching lever 20and rotating such latching lever about the hinge pin 21 to itshorizontal extended limit, thus forming a handle for manipulation of thecover.

Some of the many advantages of the present invention should now bereadily apparent. The inventive latch provides for means of limiting theamount of displacement of a pressurized cover after the release thereof,such means being both positive, reliable and not depending on thecontinued integrity of elastic elements like springs or other similarbiasing devices. Furthermore, the latch provides a convenient handle formanipulating the cover after the pressure is released from within thecontainer.

Obviously, many modifications and variations of the present inventionmay be made with regard to the foregoing detailed description withoutdeparting from the spirit of the invention.

We claim:

1. A latching apparatus for providing an increment of free displacementof a container cover, comprising:

a latching lever pivotally suspended at the upper end thereof from theperiphery of the cover;

a catch formed on the container in opposing alignment with said latchinglever;

a projection formed on the lower end of said lever extending apredetermined increment below said catch for engagement therewith at apredetermined increment of opening of the cover;

weight bias means formed on said lever horizontally distal of thepivotal connection at the periphery of the cover for urging by gravitysaid projection into engaging alignment with said catch; and

limit means formed on said lever proximate the upper end thereof forlimiting the pivotal rotation thereof between a substantially horizontalextended position and a vertical suspended position.

2. Apparatus according to claim 1 wherein:

said limit means including a first projecting structure extendingradially from the pivot connection of said lever for abutting against anopposing surface of the cover when said lever is extended to ahorizontal position and a second projecting structure extendingtransversely from said lever to oppose a peripheral edge of the coverwhen said lever is in a vertically suspended position.

3. Apparatus according to claim 2 further comprising:

a permanent magnet formed on the exterior of the container in opposingrelationship with said projection.

4. Apparatus according to claim 3 wherein:

said second projecting structure is dimensioned to oppose the inwardrotation of said lever at an angular position maintaining the adjacentend of said projection at a predetermined increment of separation fromthe opposing surface of said magnet.

5. Apparatus for providing a pressure release opening in a container,comprising:

a cover pivotally mounted on the container for closing a horizontalopening formed therein;

releasable securing means attached to said container for selectivelysealably securing said cover to said opening;

a latching lever pivotally suspended at the upper end thereof from theperiphery of the cover at a point substantially opposite to the pivotalconnection of said cover;

a catch formed on the container in opposing alignment with said latchinglever;

a projection formed on the lower end of said lever extending apredetermined increment below said catch for engagement therewith at apredetermined increment of opening of the cover;

weight bias means formed on said lever horizontally distal of thepivotal connection at the periphery of the cover for urging by gravitysaid projection into engaging alignment with said catch; and

a first projecting structure extending radially from the pivotconnection of said lever for abutting against an opposing surface of thecover when said lever is extended to a horizontal position and a secondprojecting structure extending transversely from said lever to oppose aperipheral edge of the cover when said lever is in a verticallysuspended position.

6. Apparatus according to claim 5 further compris- 5 ing:

tion from the opposing surface of said magnet. l

1. A latching apparatus for providing an increment of free displacementof a container cover, comprising: a latching lever pivotally suspendedat the upper end thereof from the periphery of the cover; a catch formedon the container in opposing alignment with said latching lever; aprojection formed on the lower end of said lever extending apredetermined increment below said catch for engagement therewith at apredetermined increment of opening of the cover; weight bias meansformed on said lever horizontally distal of the pivotal connection atthe periphery of the cover for urging by gravity said projection intoengaging alignment with said catch; and limit means formed on said leverproximate the upper end thereof for limiting the pivotal rotationthereof between a substantially horizontal extended position and avertical suspended position.
 2. Apparatus according to claim 1 wherein:said limit means including a first projecting structure extendingradially from the pivot connection of said lever for abutting against anopposing surface of the cover when said lever is extended to ahorizontal position and a second projecting structure extendingtransversely from said lever to oppose a peripheral edge of the coverwhen said lever is in a vertically suspended position.
 3. Apparatusaccording to claim 2 further comprising: a permanent magnet formed onthe exterior of the container in opposing relationship with saidprojection.
 4. Apparatus according to claim 3 wherein: said secondprojecting structure is dimensioned to oppose the inward rotation ofsaid lever at an angular position maintaining the adjacent end of saidprojection at a predetermined increment of separation from the opposingsurface of said magnet.
 5. Apparatus for providing a pressure releaseopening in a container, comprising: a cover pivotally mounted on thecontainer for closing a horizontal opening formed therein; releasablesecuring means attached to said container for selectively sealablysecuring said cover to said opening; a latching lever pivotallysuspended at the upper end thereof from the periphery of the cover at apoint substantially opposite to the pivotal connection of said cover; acatch formed on the container in opposing alignment with said latchinglever; a projection formed on the lower end of said lever extending apredetermined increment below said catch for engagement therewith at apredetermined increment of opening of the cover; weight bias meansformed on said lever horizontally distal of the pivotal connection atthe periphery of the cover for urging by gravity said projection intoengaging alignment with said catch; and a first projecting structureextending radially from the pivot connection of said lever for abuttingagainst an opposing surface of the cover when said lever is extended toa horizontal position and a second projecting structure extendingtransversely from said lever to oppose a peripheral edge of the coverwhen said lever is in a vertically suspended position.
 6. Apparatusaccording to claim 5 further comprising: a permanent magnet formed onthe exterior of the container in opposing relationship with saidprojection.
 7. Apparatus according to claim 6 wherein: said secondprojecting structure is dimensioned to oppose the inward rotation ofsaid lever at an angular position maintaining the adjaCent end of saidprojection at a predetermined increment of separation from the opposingsurface of said magnet.